U.S. patent application number 10/392812 was filed with the patent office on 2003-11-27 for multilayered-stretched resin film.
This patent application is currently assigned to YUPO CORPORATION. Invention is credited to Kimura, Kazuyuki, Yamanaka, Masaaki.
Application Number | 20030219585 10/392812 |
Document ID | / |
Family ID | 26600376 |
Filed Date | 2003-11-27 |
United States Patent
Application |
20030219585 |
Kind Code |
A1 |
Yamanaka, Masaaki ; et
al. |
November 27, 2003 |
Multilayered-stretched resin film
Abstract
Disclosed is a multilayered-stretched resin film characterized
in that on the back surface of a printable front layer (A)
comprising a thermoplastic resin, an inorganic finepowder, and/or
an organic filler is laminated a back layer (B) comprising a
surface-treated inorganic finepowder and a thermoplastic resin
comprising a hydrophilic thermoplastic resin, and in that the peel
strength of back layer (B) is from 10 to 200 g/cm. The
multilayered-stretched resin film affords good suitability for
printing and embossing, that can be directly adhered to a wall or
the like using a water-soluble adhesive without necessitating a
backing of natural paper required by conventional wallpapers, and
that can be readily peeled off the wall in a manner permitting
recycling.
Inventors: |
Yamanaka, Masaaki;
(Kashima-gun, JP) ; Kimura, Kazuyuki;
(Kashima-gun, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
YUPO CORPORATION
Chiyoda-ku
JP
|
Family ID: |
26600376 |
Appl. No.: |
10/392812 |
Filed: |
March 21, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10392812 |
Mar 21, 2003 |
|
|
|
PCT/JP01/08100 |
Sep 18, 2001 |
|
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Current U.S.
Class: |
428/304.4 ;
428/343 |
Current CPC
Class: |
B32B 2307/75 20130101;
Y10T 428/25 20150115; B32B 27/18 20130101; B32B 27/16 20130101;
B32B 27/34 20130101; B32B 2264/10 20130101; B32B 2307/72 20130101;
B32B 2607/02 20130101; B32B 27/08 20130101; B32B 27/32 20130101;
B32B 2307/728 20130101; B32B 2307/732 20130101; B32B 2307/726
20130101; B32B 2307/402 20130101; B32B 27/20 20130101; B32B 3/30
20130101; B32B 27/306 20130101; Y10T 428/249953 20150401; B32B 3/26
20130101; B32B 27/308 20130101; B32B 2307/21 20130101; B32B 27/36
20130101; B32B 2307/5825 20130101; B32B 2274/00 20130101; Y10T
428/28 20150115 |
Class at
Publication: |
428/304.4 ;
428/343 |
International
Class: |
B32B 007/12; B32B
003/26; B32B 015/04 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 21, 2000 |
JP |
P2000-286266 |
Oct 31, 2000 |
JP |
P2000-332690 |
Claims
What is claimed is:
1. A multilayered-stretched resin film characterized in that on the
back surface of a printable front layer (A) comprising a
thermoplastic resin, an inorganic finepowder, and/or an organic
filler is laminated a back layer (B) comprising a surface-treated
inorganic finepowder and a thermoplastic resin comprising a
hydrophilic thermoplastic resin, and in that the peel strength of
back layer (B) is from 10 to 200 g/cm.
2. The multilayered-stretched resin film according to claim 1
wherein the liquid water-absorption volume as measured by Japan
TAPPI NO. 51-87 of said back layer (B) is from 6 to 50
mL/m.sup.2.
3. The multilayered-stretched resin film according to claim 1 or 2
wherein said thermoplastic resin is an olefin-based resin, an
olefin-based thermoplastic elastomer, or a mixture of an
olefin-based resin and an olefin-based thermoplastic elastomer.
4. The multilayered-stretched resin film according to claim 3
wherein said mixture of olefin-based resin and olefin-based
thermoplastic elastomer comprises from 10 to 300 weight parts of
olefin thermoplastic elastomer per 100 weight parts of olefin-based
resin.
5. The multilayered-stretched resin film according to claim 3 or 4
wherein the melting point of said olefin-based thermoplastic
elastomer is greater than or equal to 160.degree. C.
6. The multilayered-stretched resin film according to claim 1
wherein said back layer (B) comprises from 3 to 200 weight parts of
said hydrophilic thermoplastic resin per 100 weight parts of
nonhydrophilic thermoplastic resin.
7. The multilayered-stretched resin film according to any one of
claims 1 to 6 wherein said hydrophilic thermoplastic resin is an
alkylene oxide polymer.
8. The multilayered-stretched resin film according to any one of
claims 1 to 7 wherein the surface of the inorganic finepowder
employed in back layer (B) is treated with at least one selected
from the group consisting of anionic surfactants, cationic
surfactants, nonionic surfactants, and antistatic agents.
9. The multilayered-stretched resin film according to any one of
claims 1 to 8 wherein the porosity of said multilayered-stretched
resin film is from 10 to 60 percent.
10. The multilayered-stretched resin film according to any one of
claims 1 to 9 wherein the porosity of back layer (B) is greater
than the porosity of front layer (A).
11. The multilayered-stretched resin film according to any one of
claims 1 to 10 wherein the average contact angle of water of back
layer (B) is from 10 to 80.degree..
12. The multilayered-stretched resin film according to any one of
claims 1 to 11 wherein the density of the multilayered-stretched
resin film is from 0.4 to 1 g/cm.sup.3.
13. The multilayered-stretched resin film according to any one of
claims 1 to 12 which is prepared by laminating front layer (A) and
back layer (B) and then stretched the laminate.
14. The multilayered-stretched resin film according to claim 13
wherein both front layer (A) and back layer (B) are stretched in at
least one axial direction.
15. The multilayered-stretched resin film according to any one of
claims 1 to 14 wherein front layer (A) and back layer (B) are
subjected to oxidation treatment.
16. The multilayered-stretched resin film according to any one of
claims 1 to 15 wherein front layer (A) is printed and then
embossed.
17. The multilayered-stretched resin film according to any one of
claims 1 to 16 wherein the multilayered-stretched resin film is
used for adhesive application and a water-soluble adhesive is
coated on back layer (B).
18. The multilayered-stretched resin film according to claim 17
wherein said water-soluble adhesive is one selected from the group
consisting of starch, polyacrylic acid, polyacrylamide,
polyethylene oxide, polyvinyl alcohol, carboxymethyl cellulose,
vinyl acetate, and polyvinyl amide.
Description
TECHNICAL FIELD
[0001] The present invention relates to a multilayered-stretched
resin film that is useful as an interior design material. More
particularly, the present invention relates to a
multilayered-stretched resin film affording good suitability for
printing and embossing, that can be directly adhered to a wall or
the like using a water-soluble adhesive without necessitating a
backing of natural paper required by conventional wallpapers, and
that can be readily peeled off the wall in a manner permitting
recycling.
BACKGROUND ART
[0002] Various kinds of paste-foamed materials and calendered films
comprising mainly of polyvinyl chloride (PVC) resin have
conventionally been employed as resin films for interior decoration
materials (especially wallpaper). Wallpapers employing these PVC
resins have problems in that chloride gas is generated when the
wallpaper is disposed or in fires and environmental pollutions such
as an indoor pollution is caused due to bleeding of the
plasticizer. Thus, to solve these problems, wallpaper films
employing polyolefin and paste-foaming methods employing polyolefin
resin have recently been developed.
[0003] Further, in order to utilize these resin films as
wallpapers, various materials have been provided as backing on the
back side of the resin film or, in the case of tack paper-type
wallpaper, a pressure sensitive adhesive or the like is applied.
When applied directly to the wall or gypsum board, an adhesive (or
paste) has conventionally been applied. Natural paper has typically
been employed as the backing material since it shows good
adhesiveness (strength) to adhesives and agglutinants, and is easy
to dry. However, when natural paper of a composition differing from
that of the resin material in the wallpaper is employed as backing,
there is a problem in that wallpaper that is peeled-off for
replacement cannot be recycled as is. Before recycling, the resin
material and the paper backing must be separated. This separation
is difficult and has proved to be problematic.
[0004] In tack paper-type wallpaper having a pressure-sensitive
adhesive comprising a synthetic resin as a main component on its
back side, it is also difficult to separate the pressure-sensitive
adhesive from the resin material. Thus, if it is tried, a large
quantity of pressure-sensitive adhesive remains adhering to the
resin material. During recycling, the resin material with the
pressure-sensitive adhesive undergoes heat decomposition and
generates extraneous substances, and the fluidity of the resin
changes greatly. These changes cause a quality problem.
[0005] Recently, to solve these problems, wallpapers devised to
permit the separation of the wallpaper resin material and the
backing (natural paper) have been proposed. For example, Japanese
Unexamined Patent Publication (KOKAI) Heisei No. 6-173200 proposes
a wallpaper that is obtained by forming a coating layer mainly
comprising water-soluble polymer and a PVC resin-based or vinyl
acetate-based synthetic binder on backing paper and laminating PVC
resin thereon. The PVC resin can be separated from the backing
paper by soaking the wallpaper in a hot water or an alkaline
solution with stirring. Japanese Unexamined Patent Publication
(KOKAI) Heisei No. 11-293600 proposes a wallpaper in which a PET
film, PP film, or the like is laminated between the backing paper
and a foam gelled PVC material. However, since there needs an
additional step of separating the backing paper when using either
of these wallpapers, there are problems in that the cost of
recycling is increased and in that the quality of the recycled
resin material drops, rendering these wallpapers impractical. Thus,
disposed wallpaper is still being mostly buried or incinerated, and
not recycled.
[0006] In light of these problems of prior art, the present
invention has for its object to provide a multilayered-stretched
resin film affording good suitability for printing and embossing,
having good coating properties without backing paper or
pressure-sensitive adhesive processing, peeling easily off the wall
or board in a recyclable manner, and being useful as a
single-material wallpaper.
DISCLOSURE OF THE INVENTION
[0007] As a result of extensive research, the present inventors
discovered that employing a hydrophilic thermoplastic resin in the
back layer and adjusting the peel strength and water-absorption
volume of the back layer to within prescribed ranges made it
possible to obtain a film having good characteristics achieving the
desired results; the present invention was devised on that
basis.
[0008] That is, the present invention provides a
multilayered-stretched resin film characterized in that on the back
surface of a printable front layer (A) comprising a thermoplastic
resin, an inorganic finepowder, and/or an organic filler is
laminated a back layer (B) comprising a surface-treated inorganic
finepowder and a thermoplastic resin comprising a hydrophilic
thermoplastic resin, and in that the peel strength of back layer
(B) is from 10 to 200 g/cm.
[0009] In preferred implementation modes of the present invention,
back layer (B) comprises from 3 to 200 weight parts of hydrophilic
thermoplastic resin per 100 weight parts of nonhydrophilic
thermoplastic resin. Further, the thermoplastic resin is desirably
an olefin-based resin, olefin-based thermoplastic elastomer, or a
mixture thereof. The olefin thermoplastic elastomer employed
desirably has a melting point of greater than or equal to
160.degree. C. In particular, from 10 to 300 weight parts of
olefin-based thermoplastic elastomer are desirably incorporated per
100 weight parts of olefin-based resin. The hydrophilic
thermoplastic resin is desirably an alkylene oxide polymer.
Further, the outer surface of the inorganic finepowder employed in
back layer (B) is desirably treated with at least one selected from
the group consisting of anionic surfactants, cationic surfactants,
nonionic surfactants, and antistatic agents. The liquid
water-absorption volume of back layer (B) is desirably from 6 to 50
mL/m.sup.2 as measured by Japan TAPPI No. 51-87.
[0010] The porosity of the multilayered-stretched resin film of the
present invention is desirably from 10 to 60 percent, and the
porosity of back layer (B) is desirably greater than that of front
layer (A). The average contact angle of water is desirably from 10
to 80.degree.. The density of the multilayered-stretched resin film
of the present invention is desirably from 0.4 to 1 g/cm.sup.3. The
multilayered-stretched resin film is desirably stretched after
laminating front layer (A) and back layer (B), with uniaxial
stretching being preferred. Front layer (A) and back layer (B) are
also desirably subjected to oxidation treatment.
[0011] Front layer (A) is desirably embossed following printing. In
particular, it is desirable for a water-soluble adhesive to be
directly coated on back layer (B), and for the wallpaper to be
adhered to the wall. The water-soluble adhesive employed on back
layer (B) is desirably at least one selected from the group
consisting of starch, polyacrylic acid, polyacrylamide,
polyethylene oxide, polyvinyl alcohol, carboxymethyl cellulose,
vinyl acetate, and polyvinyl amide.
DETAILED DESCRIPTION OF THE INVENTION
[0012] The multilayered-stretched resin film of the present
invention is described in detail below. In the present
specification, ranges indicated with "to" mean ranges including the
numerical values before and after "-" as the minimum and maximum
values.
[0013] The multilayered-stretched resin film of the present
invention comprises at least a front layer (A) and a back layer
(B). Front layer (A) comprises a thermoplastic resin, an inorganic
finepowder, and/or an organic filler. Back layer (B) comprises
thermoplastic resin comprising a hydrophilic thermoplastic resin,
and a surface-treated inorganic finepowder. Front layer (A) and
back layer (B) desirably comprise thermoplastic resin as an
olefin-based thermoplastic elastomer.
[0014] Configuration of Front Layer (A)
[0015] Front layer (A) of the multilayered-stretched resin film of
the present invention can be printed in a variety of manners and
then treated by embossing or the like. The application of such a
treatment permits the useful application of the
multilayered-stretched resin film of the present invention as
wallpaper or the like. Based on the use of the
multilayered-stretched resin film, front layer (A) can be
configured to be suitable to various high-precision printing by a
variety of printing methods, and have adequate adhesive strength to
hold ink during embossing following printing.
[0016] The thermoplastic resin employed in front layer (A) is not
specifically limited. The thermoplastic resin of preference
incorporates an olefin-based thermoplastic elastomer as the
thermoplastic resin. So long as an olefin-based thermoplastic
elastomer is incorporated, neither the type nor composition of the
other resins contained in the front layer (A) are specifically
limited.
[0017] Olefin-based resins are employed with preference in addition
to the olefin-based thermoplastic elastomer. Specific examples are
ethylene, propylene, 1-butene, 1-hexene, 1-heptene, 1-octene,
4-methyl-1-pentene, 3-methyl-1-pentene, and other homopolymers of
alpha-olefin having 2 to 8 carbon atoms, as well as copolymers
comprising from 2 to 5 kinds of these alpha-olefins. The copolymers
may be random copolymers or block copolymers. Specific examples are
branched ethylene, linear polyethylene, high-density polyethylene,
and linear low-density polyethylene with a density of from 0.89 to
0.97 g/cm.sup.3 and a melt flow rate (190.degree. C., 2.16 kg load)
of from 1 to 10 g/10 min; propylene homopolymer, propylene ethylene
copolymer, propylene 1-butene copolymer, propylene ethylene
1-butene copolymer, propylene 4-methyl-1-pentene copolymer,
propylene 3-methyl-1-pentene copolymer, poly(1-butene),
poly(4-methyl-1-pentene), and propylene ethylene 3-methyl-1-pentene
copolymer with a melt flow rate (230.degree. C., 2.16 kg load) of
from 0.2 to 20 g/10 min.
[0018] Of these, propylene homopolymers, propylene ethylene random
copolymers, high-density polyethylene, and linear low-density
polyethylene are preferred because they are inexpensive and afford
good molding properties.
[0019] An olefin-based thermoplastic elastomer in the form of a
compound material comprised of olefin-based elastomer and
olefin-based resin is desirably employed as the thermoplastic resin
in front layer (A). In particular, three preferred examples are
given below:
[0020] (1) a mixture prepared by simply blending an olefin-based
elastomer as a soft segment and an olefin-based elastomer as a hard
segment;
[0021] (2) a compound combined by partially crosslinking or
polymerizing an olefin-based elastomer and an olefin based resin;
and
[0022] (3) a compound obtained by crosslinking an olefin-based
elastomer and dispersing it in an olefin-based resin.
[0023] Ethylene-based rubbers typified by EPDM are examples of the
above-described olefin-based elastomers. Examples of olefin-based
resins are polyethylene and propylene-based resins.
[0024] The melting point (DSC peak temperature) of the olefin-based
thermoplastic elastomer employed in front layer (A) and back layer
(B) is desirably greater than or equal to 160.degree. C.,
preferably from 165 to 180.degree. C. When an olefin-based
thermoplastic elastomer having such a desired melting point is
employed, front layer (A) is imparted with good suitability for
embossing, the film rigidity required for application to the wall
surface, and flexibility to absorb unevenness on the wall surface
following application. Further, it becomes easy to ensure that the
porosity of back layer (B) is greater than that of front layer (A)
so that peeling starts in back layer (B).
[0025] Additives such as coloring pigments, flame retardants,
oxidation inhibitors, dispersing agents, mildew-combatting agents,
antibacterial agents, and UV-stabilizers may be added as needed to
the above-described olefin-based thermoplastic elastomer and
thermoplastic resin.
[0026] In the present invention, the above-described olefin-based
thermoplastic elastomers may be employed singly or in combinations
of two or more.
[0027] From 10 to 300, preferably from 20 to 80, weight parts of
the olefin-based thermoplastic elastomer are desirably incorporated
per 100 weight parts of olefin-based resin into front layer
(A).
[0028] An inorganic finepowder and/or an organic filler are
employed in front layer (A).
[0029] The type of inorganic finepowder is not specifically
limited. However, examples are heavy calcium carbonate, light
calcium carbonate, clay, talc, titanium dioxide, barium sulfate,
zinc oxide, magnesium oxide, diatomaceous earth, and silicon oxide
with an average particle diameter of from 0.1 to 3 micrometers. Of
these, light and heavy calcium carbonate, clay, diatomaceous earth,
and titanium dioxide are preferred due to low cost and good
formability of voids generated during shaping by stretching.
[0030] The type of organic filler is not specifically limited.
However, a resin differing from the main component thermoplastic
resin and having an average particle diameter of from 0.1 to 3
micrometers following dispersion is desirable. For example, when
the thermoplastic resin film is an olefin-based resin film,
examples of the organic filler are polyethylene terephthalate,
polybutylene terephthalate, polycarbonate, nylon 6, nylon 6,6,
cyclic olefin homopolymers, and copolymers of cyclic olefin and
ethylene, with a melting point of from 120 to 300.degree. C. or a
glass transition temperature of from 120 to 280.degree. C.
[0031] Dispersing agents, oxidation inhibitors, UV-stabilizers, and
compatibility-enhancing agents are desirably added in the course of
blending and kneading these organic fillers into the olefin-based
resins. The quantity and type of compatibility-enhancing agent
selected is particularly important because it determines the shape
of the particles of the organic filler.
[0032] An inorganic finepowder or organic filler containing coarse
particles exceeding 44 micrometers in as small amount as possible
is desirably selected to prevent voids during printing. The use in
front layer (A) of an inorganic finepowder or organic filler having
an average particle diameter smaller than the inorganic finepowder
or organic filler employed in back layer (B) makes it possible that
the amount of the voids generated during stretching in front layer
(A) are smaller than that in back layer (B). This constitution
enables improved surface strength and high-precision printing, and
this constitution also permits the elimination of failed surface
peeling and the like when employed as wallpaper and improves
manufacturing properties by permitting embossing at lower
temperature.
[0033] Just one from among the above-described inorganic
finepowders and organic fillers may be selected for use, or two or
more may be employed in combination in front layer (A). When
employing two or more, it is possible to mix an inorganic
finepowder with an organic filler for use.
[0034] It is particularly desirable that front layer (A) comprises
10 to 60 weight percent of organic filler and/or inorganic
finepowder having an average particle diameter of from 0.1 to 3
micrometers and 40 to 90 weight percent of the mixture of
olefin-based resin and olefin-based thermoplastic elastomer in
front layer (A).
[0035] In case the quantity of inorganic finepowder and/or organic
filler is less than 10 weight percent, ink adhesion tends to
deteriorate. In case 60 weight percent is exceeded, uniform
stretching becomes difficult, tears occur in the surface of the
stretched film, and practical use tends to be precluded. In case
the average particle diameter of the inorganic finepowder and/or
organic filler is less than 0.1 micrometer, secondary aggregation
occurs due to poor dispersion in the thermoplastic resin, numerous
protrusions are present on the surface, and high-precision printing
tends to be precluded. In case 3 micrometers are exceeded, the
flatness of the surface decreases and, similarly, high-precision
printing tends to be precluded.
[0036] In case the multilayered-stretched resin film of the present
invention is applied as wallpaper or it is desired to inhibit
decrease over time in the strength of an applied durable material
and decrease over time in the adhesive strength of the printed ink,
it is preferred that oxidation inhibitors, UV-stabilizers, titanium
dioxide, or the like is added to front layer (A).
[0037] Configuration of Back Layer (B)
[0038] Back layer (B) of the multilayered-stretched resin film of
the present invention comprises a thermoplastic resin containing a
hydrophilic thermoplastic resin, and surface-treated inorganic
finepowder. The peel strength of back layer (B) is desirably from
10 to 200 g/cm, preferably from 20 to 160 g/cm, and more preferably
from 30 to 150 g/cm. The liquid water-absorption volume of back
layer (B) is desirably from 6 to 50 mL/m.sup.2, preferably from 10
to 45 mL/m.sup.2, and more preferably from 14 to 40 mL/m.sup.2.
[0039] A back layer (B) having the above-stated characteristics can
be readily embossed to impart a sense of perspective. Further, back
layer (B) affords good drying of the adhesive when a water-soluble
adhesive is applied and is well-suited to application with good
adhesion to the wall, board, or the like. Thus, the application of
a water-soluble adhesive to back layer (B) permits the application
of the multilayered-stretched resin film of the present invention
directly to the wall or the like. When peeling the
multilayered-stretched resin film of the present invention once it
has been applied, some of the material of back layer (B) and the
adhesive remain on the wall or the like, facilitating recycling.
This advantage permits the useful application of the
multilayered-stretched resin film of the present invention as
wallpaper or the like.
[0040] A hydrophilic thermoplastic resin is employed in back layer
(B) of the multilayered-stretched resin film of the present
invention. The "hydrophilic thermoplastic resin" referred to here
is one that dissolves to a water at a room temperature within 30
minutes, or has a water-absorption factor at a room temperature of
greater than 3 g/g, preferably from 5 to 50 g/g. The terminology
"water-absorption factor" is determined by dividing the weight
after the water absorption by the weight prior to the water
absorption. The water-absorption is carried out by molding
hydrophilic thermoplastic resin through a T-die connected to an
extruder or hot press to a thickness of about 0.1 mm to obtain a
sheet, and soaking the sheet in distilled water for 30 min at room
temperature, for example, at 25.degree. C. to absorb water. In the
present specification, thermoplastic resins that do not satisfy
such conditions are referred to as nonhydrophilic thermoplastic
resins. Further, in the present specification, the term
"thermoplastic resin" is a concept encompassing both hydrophilic
thermoplastic resins and nonhydrophilic thermoplastic resins.
[0041] Examples of hydrophilic thermoplastic resins suitable for
use in back layer (B) are: polyvinyl resins such as polyvinyl
alcohol and polymers and crosslinked products thereof, and
polyvinyl pyrrolidone and polymers thereof; polymers and
crosslinked products of esters of maleic acid, methacrylic acid,
and acrylic acid having hydroxyalkyl groups such as 2-hydroxyethyl
group and 2-hydroxypropyl group, polyacryl amides and their
polymers, hydrolytes of polymers and crosslinked polymers of
acrylonitriles, polyacrylic-based resins such as polymers and
copolymers of acrylic acid and methacrylic acid, salts thereof
(such as sodium salts, potassium salts, lithium salts, and
primary-quaternary ammonium salts), and hydrolytes of copolymers of
vinyl acetate and methyl methacrylate; water-soluble nylon;
urethane resins (such as water-soluble polyurethane, highly water
absorptive polyurethane, thermoplastic polyurethane); polyalkylene
oxide resins such as polyethylene oxide and polymers thereof and
polypropylene oxide and polymers thereof; polyether amide,
polyether ester amide; polyvinyl amine, polyallyl amine, and
polymers thereof.
[0042] Of these, the compounds of preference are polyalkylene oxide
polymers and polyether ester amides due to their high water
absorption and the ease of film molding.
[0043] The nonhydrophilic thermoplastic resin employed in back
layer (B) is not specifically limited. For example, the
olefin-based resins and thermoplastic elastomers described for
front layer (A) above may also be employed in back layer (B). The
nonhydrophilic thermoplastic resin employed in back layer (B) may
be identical to, or different from, that employed in front layer
(A).
[0044] The blending ratio when mixing the hydrophilic thermoplastic
resin and the nonhydrophilic thermoplastic resin is desirably from
3 to 200 weight parts, preferably from 5 to 100 weight parts, of
hydrophilic thermoplastic resin per 100 weight parts of
nonhydrophilic thermoplastic resin to achieve film formability,
stretching properties, and water absorption.
[0045] To prevent the deterioration over time of the
multilayered-stretched resin film as a durable material, oxidation
inhibitors and UV stabilizers are desirably added to back layer
(B). Flame retardants may also be added as needed.
[0046] A surface-treated inorganic finepowder is employed in back
layer (B). For example, surface-treated inorganic finepowders are
obtained by treating heavy calcium carbonate with a water-soluble
anionic, cationic, or nonionic surfactant having an average
molecular weight of from 1,000 to 150,000 during wet comminution;
treating heavy calcium carbonate with an anionic, cationic, or
nonionic antistatic agent during wet comminution; and treating
heavy calcium carbonate in two stages with the above-listed
surfactants and antistatic agents.
[0047] The average contact angle of water of back layer (B) is
desirably from 10 to 80.degree., preferably from 15 to 65.degree.,
and more preferably from 20 to 50.degree.. The use of a finepowder
obtained by treating a finepowder having an average particle
diameter of from 0.5 to 10 micrometers in a two-stage treatment
with a surfactant and antistatic agent to achieve such a desirable
hydrophilic surface is particularly desirable.
[0048] An inorganic finepowder and/or an organic filler that have
not been surface treated may be employed in combination with the
surface-treated inorganic finepowder in back layer (B). The types
of inorganic finepowders and/or organic fillers that can be
employed in back layer (B) are not specifically limited; they may
be suitably selected for use from among the inorganic finepowders
and organic fillers described above as being suitable for use in
front layer (A). Either the inorganic finepowder or organic filler
may be employed singly or in combinations of two or more. When
employed in a combination of two or more, the inorganic finepowder
and organic filler may be employed in combination.
[0049] The porosity of the multilayered-stretched resin film of the
present invention is desirably from 10 to 60 percent. To achieve a
porosity falling within the desired range, the quantity of
surface-treated inorganic finepowder of back layer (B) desirably
falls within a range of from 30 to 70 percent by weight, preferably
35 to 65 percent by weight.
[0050] When the surface-treated inorganic finepowder is employed at
less than 30 weight percent and the average particle diameter of
the surface-treated inorganic finepowder is less than 0.5
micrometer, less voids are generated, tending to result in poor
suitability for embossing (application of embossing). Further, the
ability of the wallpaper to conceal is inadequate, the texture of
the wall is visible, flexibility is inadequate in a manner
rendering irregularities on the while conspicuous, and there is a
tendency not to achieve a sense of quality. High water absorption
also tends not to be achieved.
[0051] When either the surface-treated inorganic finepowder exceeds
70 weight percent or the average particle diameter is greater or
equal to 10 micrometers, it becomes difficult to achieve uniform
stretching and tears tend to appear in the surface of the film
obtained by stretching.
[0052] The peel strength of back layer (B) is from 10 to 200 g/cm,
preferably from 20 to 160 g/cm. When the peel strength is less than
10 g/cm, separation tends to occur during or following the hanging
of wallpaper, which is impractical. When 200 g/cm is exceeded,
peeling from the back layer (B) portion is precluded, compromising
recycling and rehanging properties.
[0053] The porosity of back layer (B) is desirably greater than
that of front layer (A). Making the porosity of back layer (B)
greater allows easy peeling from the back layer (B) portion when
peeling off the wall a multilayered-stretched resin film that has
been applied to a wall.
[0054] When either the liquid water-absorption volume of back layer
(B) as measured by the Japan TAPPI No. 51-87 exceeds 50 mL/m.sup.2
or the contact angle of water is less than 10.degree., the water
absorption rate becomes excessively high. Thus, when a
water-soluble adhesive is employed, there is a tendency for a large
amount of the adhesive component to penetrate into the interior.
Thus, the cost of application tends to rise because of the larger
quantity of adhesive that must be applied. Further, there is a
tendency that drying of the adhesive occurs prior to hanging on the
wall and thereby hanging becomes difficult.
[0055] When either the liquid absorption volume is less than 6
mL/m.sup.2 or the average contact angle of water exceeds
80.degree., the water absorption rate tends to decrease and the
adhesive tends to dry slowly. Thus, wallpaper that has been hung on
the wall tends to bulge and curl, tending to greatly compromise the
ease of application. Further, since little adhesive component
impregnates the film, adhesion between the adhesive and the
multilayered-stretched resin film tends to diminish.
[0056] Other Layers
[0057] So long as the multilayered-stretched resin film of the
present invention comprises front layer (A) and back layer (B)
satisfying the conditions of the present invention, it may also
comprise other layers. For example, one or more intermediate layers
(C) may be provided between front layer (A) and back layer (B).
[0058] Considering embossing applicability, intermediate layer (C)
desirably has a porosity roughly identical to that of back layer
(B). However, to prevent peeling from starting in intermediate
layer (C) when peeling the wallpaper from the wall surface or the
like, the porosities of the individual layers desirably satisfy the
following relations:
Back layer (B)>intermediate layer (C)>front layer (A)
[0059] Further, the difference in porosity between back layer (B)
and front layer (A) is desirably greater than or equal to 20
percent.
[0060] The thickness of the multilayered-stretched resin film of
the present invention is desirably from 30 to 500 micrometers,
preferably from 40 to 400 micrometers. It is possible to achieve a
thickness of over 1 mm by adhesion with various adhesives.
[0061] A ratio of thickness (A)/(B) of front layer (A) to back
layer (B) of (1 to 7)/(9 to 3) is desirable from the perspectives
of film strength, suitability for printing, ease of embossing, and
embossing reversion. When the thickness ratio of back layer (B) is
less than 30 percent, the embossing tends not to take hold.
Further, the amount of water-soluble adhesive absorbed is
inadequate, causing the adhesive to tend to dry poorly. When an
intermediate layer (C) is provided, it is desirable to include the
thickness of layer (C) together with that of back layer (B) when
weighing these considerations.
[0062] Manufacturing and Processing of the Multilayered-Stretched
Resin Film
[0063] The multilayered-stretched resin film of the present
invention can be manufactured by combining various methods known to
those skilled in the art. A multilayered-stretched resin film
manufactured by any method is covered by the scope of the present
invention so long as it satisfies the conditions described in claim
1.
[0064] The multilayered-stretched resin film of the present
invention may be manufactured by first separately stretching front
layer (A) and back layer (B) and then laminating them, or may be
manufactured by first laminating front layer (A) and back layer (B)
and them stretching them together. When intermediate layer (C) is
present, the three layers may be first separately stretched and
then laminated, or first laminated and then collectively stretched.
Alternatively, front layer (A) and intermediate layer (C) may be
first laminated and stretched, after which stretched or unstretched
back layer (B) may be laminated. These methods may also be suitably
combined.
[0065] The preferred manufacturing method is to first laminate
front layer (A) and back layer (B), followed by collective
stretching. When intermediate layer (C) is present, front layer
(A), intermediate layer (C), and back layer (B) are desirably first
laminated and then collectively stretched. This is simpler and less
expensive than separately stretching each of the layers followed by
lamination. Further, it is easier to control the voids formed in
front layer (A) and back layer (B).
[0066] Various known methods of stretching may be employed.
Examples of specific methods of stretching include roll stretching
exploiting the difference in peripheral speed of a group of rolls,
and clip stretching in a tenter oven. Of these, uniaxial roll
stretching is preferred because is permits the adjustment of the
stretching factor to any level and permits controlling the size and
number of voids that are formed. Since the stretching orientation
of the resin is made the longitudinal direction of the film, there
is greater tensile strength than in unstretched films, making it
possible to achieve multilayered-stretched resin films undergoing
less dimensional change due to tension during printing and
processing. Such multilayered-stretched resin films are highly
useful as wallpaper.
[0067] The stretching ratio is not specifically limited and may be
suitably selected based on the objectives and the characteristics
of the thermoplastic resin being employed. For example, the
stretching ratio is from 1.2 to 12-fold, preferably from 2 to
7-fold, when a homopolymer or copolymer of propylene is employed as
the thermoplastic resin.
[0068] The stretching temperature is not specifically limited.
However, stretching is desirably conducted at a temperature that is
at least 5.degree. C. (preferably 10.degree. C.) lower than the
melting point of the thermoplastic resin employed in back layer
(B). When not at least 5.degree. C. lower, the sheets stick to the
surface of the rolls during roll stretching, and tend to adhere to
the surface of the stretched film. Further, cracks formed by the
generation of voids in back layer (B) decrease in number, causing
the liquid absorption capability to decrease. When directly hanging
wallpaper on a wall, drying of the water-soluble adhesive tends to
fail and adhesion during application tends to greatly decrease.
[0069] The multilayered-stretched resin film of the present
invention may be heat treated at a temperature higher than the
stretching temperature as needed. The heat treatment method is not
specifically limited, and may be suitably selected based on the
objective, characteristics of the resin employed, and stretching
method.
[0070] Following stretching, the multilayered-stretched resin film
has minute voids. The porosity of the multilayered-stretched resin
film of the present invention is desirably from 10 to 60 percent,
preferably from 15 to 50 percent. In the present specification, the
porosity that is given was calculated from the area ratio using an
image analyzer (Model Luzex IID, made by Nireko (K.K.)) to analyze
the holes in an area observed in a photograph taken by electron
microscopy.
[0071] When the porosity of the multilayered-stretched resin film
is less than 10 percent, the liquid (water) absorption capability
tends to be inadequate when employing a water-soluble adhesive.
When the porosity exceeds 60 percent, the liquid (water) absorption
capability tends to be excessively high, with a large quantity of
adhesive penetrating into the layers. This then necessitates the
use of a large amount of adhesive and tends to increase costs
during application.
[0072] As set forth above, the porosity of back layer (B) is
desirably greater than that of front layer (A). When the porosity
of front layer (A) is greater, there are problems with recycling
properties, suitability of the front layer to printing, and front
surface strength.
[0073] The density of the multilayered-stretched resin film of the
present invention is desirably from 0.4 to 1 g/cm.sup.3, preferably
from 0.45 to 0.95 g/cm.sup.3. The multilayered-stretched resin film
of the present invention is particularly desirable in the form of
an opaque white film having voids.
[0074] The multilayered-stretched resin film of the present
invention may be employed as is or laminated onto a separate
thermoplastic film for use. For example, another thermoplastic
resin film may be laminated onto front layer (A) of the
multilayered-stretched resin film of the present invention.
Examples of laminate films are transparent and opaque films in the
form of polyester films, polyamide films, and polyolefin films.
[0075] To improve the suitability for printing of the front layer
(A), it may be subjected to various oxidation treatments or coated
with antistatic agents, anchor coating agents, and water-repelling
agents.
[0076] To improve the hydrophilic property of the back layer (B)
and adhesion to the water-soluble adhesive, various oxidation
treatments may be conducted. Examples of oxidation treatments are
corona discharge treatment, plasma treatment, flame treatment,
glow-discharge treatment, ozone treatment, and the like. Corona
discharge treatment and flame treatment are preferred.
[0077] Printing may be conducted on the surface of the
multilayered-stretched resin film of the present invention based on
the intended use. The type and method of printing is not
specifically limited. For example, known printing methods such as
gravure printing, flexo printing, silk-screen printing, and offset
printing employing an ink in which a pigment has been dispersed in
a known vehicle may be employed. Printing may also be conducted by
metal evaporation, gloss printing, matte printing, or the like. The
print pattern may be suitably selected from among natural patterns
such as stone textures, wood grains, grids, waterdrops, and flower
patterns, as well as abstract patterns such as characters.
[0078] The multilayered-stretched resin film of the present
invention may be embossed. Embossing is generally conducted after
printing, but printing may be conducted following embossing.
[0079] For example, the embossing may be conducted by imparting the
uneven shape of an embossing plate by means of heat or pressure
with a lithographic press, roll embosser, or some other known press
or embosser. In roll embossing, the uneven shape of a cylindrical
embossing plate is imparted to the material by heat and pressure.
When imparting a shape by heat and pressure, heating is controlled
to between the thermal deformation temperature and the melting
temperature of the resin employed in front layer (A) of the
multilayered-stretched resin film, the embossing plate is pressed
against the surface of the multilayered-stretched resin film to
impart its shape, and the material is cooled to fix the shape. The
heating method employed may be, for example, infrared irradiation,
blowing hot air, heat transfer by heated rollers, and induction
heating. Imparting of an embossed shape may also be achieved
without the use of heat by methods employing pressure alone, or
imparting an embossed shape either before or after stretching at
the same time as film molding without the use of an embosser.
[0080] When employing the multilayered-stretched resin film of the
present invention to various decorative panels and fire-retardant
composite sheets, conducting wiping after embossing to fill the
interior of depressions with wiping ink permits greater creativity.
This is particularly effective in reproducing the external
appearance of wood grain on tubular members.
[0081] Further, in addition to wiping, a surface protective layer
comprised of a transparent resin layer can be formed on the
outermost layer. The surface protective layer functions both to
protect the outer surface layer and to impart a sense of
perslective to the lower layer printing or embossed designs.
Accordingly, even when employing the multilayered-stretched resin
film of the present invention in decorative panels and
fire-retardant composite sheets, a surface protective layer is
particularly useful.
[0082] The surface protective layer may be formed by coating or
bonding. To further enhance the physical characteristics of the
outer surface, a transparent or colored transparent resin with
physical surface characteristics such as good weather resistance,
abrasion resistance, and pollution resistance is desirably
employed. Preferred examples of such resins are various acrylates,
polyesters, radiation-setting resins, polyurethane, two-component
hardening resins such as unsaturated polyesters, fluorine resins,
and polysiloxane resins. Known antibacterial agents,
mildew-combatting agents, fragrance materials, and the like may be
blended into the outer surface protective layer.
[0083] Suitability of the Multilayered-Stretched Resin Film
[0084] Adhesive may be directly applied to the back side of the
multilayered-stretched resin film of the present invention, which
may then be directly adhered to wooden wall materials, gypsum
board, various composition materials (including resin-treated
decorative panels and gypsum boards), and metal sheets such as iron
and aluminum sheets. Thus, when employing the
multilayered-stretched resin film of the present invention in
wallpaper or the like, it is not necessary to provide a backing
material (natural paper or the like) on the back side. Thus, when
the multilayered-stretched resin film of the present invention that
has been hung as wallpaper is peeled off the wall, it can be
recycled as a single material because no backing (natural paper or
the like) has been mixed into the original material being
recycled.
[0085] The adhesive employed to hang the multilayered-stretched
resin film of the present invention is not specifically limited;
water-soluble adhesives, carbohydrate adhesives, synthetic resin
adhesives, and the like may be employed. The adhesive may be
soluble in a solvent or water. From the perspectives of ease of
operation and stability problems (toxicity, fires, and the like due
to vaporizing of solvent), the use of a water-soluble adhesive is
preferred.
[0086] There are water-soluble adhesives that have the property of
dissolving or swelling in water. Examples are protein-based
adhesives such as gelatin, glue, and casein.
[0087] Examples of carbohydrate adhesives are starch and
derivatives thereof, and cellulose derivatives such as hydroxyethyl
cellulose, ethylhydroxyethyl cellulose, carboxymethyl cellulose
(CMC), and viscose. Further examples are gum Arabic and gum
traganth.
[0088] Examples of synthetic resin adhesives are polyvinyl alcohol,
polyvinyl ether, and polyvinyl pyrrolidone. Further examples are
polyacryl amide, polyethylene oxide, polyvinyl amide, water-soluble
polyurethane, polyacrylic acid resins, and salts thereof.
Emulsion-based adhesives obtained by emulsion polymerization of
vinyl acetate, acrylic ester, ethylene vinyl acetate, vinyl
chloride, and the like are also examples of adhesives.
[0089] Of these, the use of a water-soluble adhesive such as a
starch or a derivative thereof, polyacrylic acid, polyacryl amide,
polyethylene oxide, polyvinyl alcohol, carboxymethyl cellulose
(CMC), vinyl acetate, or polyvinyl amide is desirable from the
perspectives of application and adhesion when hanging the
multilayered-stretched resin film of the present invention on a
wall or the like. Starches and their derivatives are the adhesives
of preference.
[0090] When the multilayered-stretched resin film of the present
invention has been peeled off the wall, water-absorbant back layer
(B) remains on the wall surface. When a water-soluble adhesive is
directly coated on back layer (B) of the multilayered-stretched
resin film of the present invention, adequate adhesion is achieved
by hanging directly onto the back layer (B) remaining on the wall
surface. That is, it is not necessary to first peel off the back
layer (B) remaining on the wall before hanging a new
multilayered-stretched resin film. The back layer (B) remaining on
the wall surface can be used for rehanging any number of times.
[0091] The multilayered-stretched resin film of the present
invention is particularly useful as wallpaper, decorative panels,
and decorative paper for flame-retardant composite sheets. It is
also useful in flooring materials, the internal furnishings of
automobiles, and in pressure sensitive adhesive labels treated for
adhesiveness.
EXAMPLES
[0092] Examples, comparative examples, and test examples are given
below to specifically describe the characteristics of the present
invention. The materials, quantities employed, ratios, processing
contents, and procedures described in the examples below can be
suitably modified without departing from the essence of the present
invention. Thus, the scope of the present invention is not to be
interpreted as being limited to the specific examples given
below.
[0093] Tables 1 and 2 give the materials employed in the examples
and comparative examples below. "MFR" in the tables stands for melt
flow rate.
1TABLE 1 Material Composition Thermoplastic Ethylene--propylene
random copolymer (product name resin (a) "Novatec PP X1804" made by
Japan Polychem (K.K.)) with MFR of 6 g/10 min (230.degree. C., 2.16
kg load), melting point 137.degree. C. (DSC peak temperature).
Thermoplastic High-density polyethylene (product name "Novatec HD
resin (b) HJ360" made by Japan Polychem (K.K.)) with MFR of 5.5
g/10 min (190.degree. C., 2.16 kg load), melting point 131.degree.
C. (DSC peak temperature). Thermoplastic Ethylene--propylene random
copolymer (product name resin (c) "Novatec PP FG3D" made by Japan
Polychem (K.K.)) with MFR of 7 g/10 min (230.degree. C., 2.16 kg
load), melting point 145.degree. C. (DSC peak temperature).
Thermoplastic Propylene homopolymer (product name "Novatec PP resin
(d) FY4" made by Japan Polychem (K.K.)) with MFR of 5 g/10 min
(230.degree. C., 2.16 kg load), melting point 164.degree. C. (DSC
peak temperature). Thermoplastic Propylene homopolymer (product
name "Novatec PP resin (e) FY6H" made by Japan Polychem (K.K.))
with MFR of 1.9 g/10 min (230.degree. C., 2.16 kg load), melting
point 164.degree. C. (DSC peak temperature). Thermoplastic Linear
low-density polyethylene (product name "Novatec resin (f) LL UF240"
made by Japan Polychem (K.K.)) with MFR of 2.1 g/10 min
(190.degree. C., 2.16 kg load), melting point 128.degree. C. (DSC
peak temperature). Elastomer (a) Olefin thermoplastic elastomer
(product name "Zelas" made by Mitsubishi Chemical) with MFR of 5.0
g/10 min (230.degree. C., 21.6 kg load), melting point 170.degree.
C. (DSC peak temperature). Elastomer (b) Olefin thermoplastic
elastomer (product name "Thermorun" made by Mitsubishi Chemical)
with MFR of 3.6 g/10 min (230.degree. C., 2.16 kg load), melting
point 152.degree. C. (DSC peak temperature). Hydrophilic Polyester
polyol resin (product name "Paoson", made by resin (1) Daiichi
Kogyo Seiyaku Co., Ltd.) Hydrophilic Polyether ester amide resin
(product name "Witistat", resin (2) made by Sanyo Kasei Co., Ltd.).
Inorganic Calcium carbonate dry comminuted to an average particle
finepowder diameter of 1.2 micrometers (product name Softon 3200
(alpha 1) made by Bihoku Hunka Kogyo (K.K)). Inorganic Calcium
carbonate dry comminuted to an average particle finepowder diameter
of 1.8 micrometers (product name Softon 2200 (alpha 2) made by
Bihoku Hunka Kogyo (K.K.)). Inorganic Calcium carbonate dry
comminuted to an average particle finepowder diameter of 8
micrometers (product name "BF100" (beta) made by Bihoku Hunka Kogyo
(K.K.)). Inorganic Calcium carbonate (product name "AFF" made by
finepowder Fimatec Ltd.) with an average particle diameter of 1.2
(gamma) micrometers treated with a water-soluble cationic
surfactant during wet comminution and surface treated with an
anionic antistatic agent.
[0094]
2TABLE 2 Material Composition Water- Starch-based adhesive (product
name "Rua Mild" made soluble by Yayoi Chemicals). adhesive ((1))
Water- Starch-based adhesive (product name "Paradyne" made soluble
by Yazawa Chemicals). adhesive ((2)) Water- Vinyl acetate adhesive
(product name "AC500" made by soluble Chuo Rika). adhesive
((3))
Example 1 to 6 and Comparative Examples 1 and 2
[0095] Multilayered-stretched resin films of the present invention
(Examples 1 to 6) and multilayered-stretched resin films for
comparison (Comparative Examples 1 and 2) were manufactured by the
following procedure and employed to manufacture wallpaper.
Comparative Example 1 is identical to the multilayered-stretched
resin film of Example 1 in Japanese Unexamined Patent Publication
(KOKAI) Heisei No. 11-348192.
[0096] Thermoplastic resin, elastomer, and inorganic finepowder
were admixed to prepare composition (A) for front layer (A).
Thermoplastic resin, hydrophilic thermoplastic resin, elastomer,
and inorganic finepowder were admixed to prepare composition (B)
for back layer (B). For Examples 4 to 6 and Comparative Examples 1
and 2, thermoplastic resin, hydrophilic thermoplastic resin,
elastomer, and inorganic finepowder were admixed to prepare
composition (C) for intermediate layer (C). The respective
materials and blending quantities were as indicated in Table 3.
[0097] When only compositions (A) and (B) were prepared, they were
melted and kneaded in two extruders set to 250.degree. C., the two
compositions were laminated in a die, the laminate was extrusion
molded and cooled to 70.degree. C. with a cooling device to obtain
a two-layer unstretched sheet.
[0098] When compositions (A), (B), and (C) were prepared, the
compositions were separately melted and kneaded in three extruders
set to 250.degree. C. Composition (A) was laminated on the front
surface side of composition (C) and composition (B) was laminated
on the back surface side of composition (C). Extrusion molding was
conducted, and the sheet was cooled to 70.degree. C. with a cooling
device to obtain a three-layer unstretched sheet.
[0099] The unstretched sheets that were formed were heated to the
stretching temperatures indicated in Table 3 and stretched to the
ratios indicated in Table 3 between longitudinal rolls. However, in
Example 4, a three-layer structure unstretched sheet was heated to
130.degree. C., stretched five-fold between rolls in the
longitudinal direction, heated to 155.degree. C., and then
stretched nine-fold in the traverse direction with a tenter
stretching device to obtain a biaxially-stretched film. Stretching
was not conducted in Comparative Example 2.
[0100] Next, both surfaces of the stretched films obtained were
corona discharge treated at 50 W/m.sup.2.multidot.min using a
discharge processor (made by Kasuga Electronics (Ltd.)) to obtain
multilayered-stretched resin films. The porosities of the
individual layers, overall porosities and densities in the
multilayered-stretched resin films obtained are given in Table
4.
[0101] After gravure printing a flower pattern (ink: product name
"CCST" made by Toyo Ink Mfg. Co., Ltd.) on front layer (A) of each
of the multilayer-stretched films, a silk surface pattern was
embossed with embossing rolls 0.5 mm in depth heated at 100.degree.
C. to obtain a wallpaper.
[0102] The water-soluble adhesives (1:1 diluted mixture with water)
indicated in Table 4 were applied with an automatic wallpaper
paster to the back layer (B) of the multilayered-stretched resin
films, and the pasted paper was immediately hung on the surface on
a gypsum board wall surface.
Comparative Examples 3 and 4
[0103] In addition to the above-described multilayered-stretched
resin film, a vinyl acetate adhesive (product name "AC-500", made
by Chuo Rika) was coated on the back layer (B) of the three-layer
structure unstretched film obtained in Comparative Example 2 and a
natural paper backing (basis weight: 80 g/m.sup.2) was adhered to
prepare Comparative Example 3. A commercial PVC wallpaper with
natural paper backing was employed as Comparative Example 4.
[0104] The front layer (A) of Comparative Example 3 and the side of
Comparative Example 4 without the natural paper backing were
gravure printed with a flower pattern (ink: product name "CSST"
made by Toyo Ink Mfg. Co., Ltd.) and a silk surface pattern was
embossed with embossing rolls 0.5 mm in depth heated at 100.degree.
C. to obtain wallpapers.
[0105] The water-soluble adhesive (1:1 diluted mixture with water)
indicated in Table 4 was applied with an automatic wallpaper paster
the paper backing side of Comparative Example 3 and 4, and the
pasted papers were immediately hung on a gypsum board surface.
Test Examples
[0106] The various multilayered-stretched resin films and
wallpapers prepared were evaluated by the following tests.
[0107] 1) Contact Angle of Water
[0108] The contact angles of water of the back layers (B) of the
various stretched resin films prepared in Examples 1 to 6 and
Comparative Examples 1 and 2 were measured ten times with a contact
angle meter (Model CA-D, made by Kyowa Interface Science Co., Ltd.)
using ion-exchange water and the average values were
calculated.
[0109] 2) Liquid Water Absorption Volume
[0110] The liquid water absorption volume of the back layer (B)
side of the various multilayered-stretched resin films prepared in
Examples 1 to 6 and Comparative Examples 1 to 4 were measured in
accordance with Japan TAPPI No. 51-87 (Paper Pulp Technology
Association, Paper Pulp Test Method No.51-87, Bristow method). That
is, a Bristow Tester II made by Kumagaya Riki Kogyo (K.K.) was
employed to add dropwise 20 microliters of a 1:20 mixed solution of
red water-based ink in ion-exchange water in a nonpressurized
state, and the liquid water absorption volume was obtained at 50 (T
1/2 ms).
[0111] 3) Peel Strength
[0112] Adhesive tape (product name "Cellotape" made by Nichiban
(K.K.)) was applied to the back layer (B) side of the various
multilayered-stretched resin films prepared in Examples 1 to 6 and
Comparative Examples 1 and 2. This was then cut to a width of 10 mm
and a length of 100 mm. Twenty-four hours later, a tension tester
(product name "Autograph", made by Shimadzu Corporation) was
employed to peel off the tape at an angle of 180 degrees at a pull
rate of 1,000 mm/min and the peel strength was measured.
[0113] 4) Suitability for Printing
[0114] Adhesive tape (product name "Cellotape" made by Nichiban
(K.K.)) was applied to the ink surface of various gravure printed
multilayered-stretched resin films and pressed well into place. The
adhesive tape was then peeled off at an angle of 90 degrees at a
constant rate and ink removal was measured based on the following
scale:
[0115] .circleincircle.: No ink removed
[0116] O: The film material was damaged, but there were no
practical problems.
[0117] .DELTA.: Most of the ink peeled off, but there was
resistance during peeling; practical problems present.
[0118] X: All ink separated, and there was no resistance during
peeling. Practical use precluded.
[0119] 5) Suitability for Embossing
[0120] (Evaluation of Embossing)
[0121] The irregularities of the embossed surfaces (front layer
(A)) of various embossed wallpapers were observed under a
magnifying glass at ten-fold magnification and evaluated on the
following scale:
[0122] O: Sense of perspective present, sharp.
[0123] .DELTA.: Sense of perspective present, but sharpness
somewhat lacking. No practical problem.
[0124] X: Depth and sharpness both lacking. Practical use
precluded.
[0125] (Evaluation of Embossing Reversion)
[0126] Water-soluble adhesive (1) indicated in Table 2 was diluted
1:1 with water and applied in suitable quantity with a brush to the
back layer (B) side of each of the embossed wallpapers and the
wallpapers were hung on a gypsum board surface in a manner
preventing the entry of air. Two sheets of board were stacked with
the sides on which wallpaper had been hung facing each other, the
boards were placed in a 60.degree. C. dryer, and 300 kg/M.sup.2 of
pressure was applied for 3 min. The boards were then removed and
the embossing was visually evaluated on the following scale:
[0127] .circleincircle.: No change
[0128] O: Slight decrease in the sense of perspective, but no
practical problem.
[0129] .DELTA.: Lack of sense of perspective, embossing reversion
clearly present, some practical problem.
[0130] X: Embossing nearly gone, practical use precluded.
[0131] 6) Ease of Hanging
[0132] (Handling Properties)
[0133] The various water-soluble adhesives indicated in Table 4
were diluted 1:1 with water and applied over an area of
90.times.180 cm with an automatic wallpaper paster (made by Kyokuto
Sanki K.K.) to the back layer (B) side (the paper backing side when
a paper backing was present) of each of the wallpapers and the
wallpapers were quickly hung on a gypsum board wall surface. The
handling properties of this series of operations were evaluated on
the following scale.
[0134] O: No wrinkling due to pasting, went on continuously and
cleanly.
[0135] .DELTA.: Some wrinkling due to pasting, time required for
hanging, some practical problems.
[0136] X: Heavy wrinkling due to pasting, did not hang cleanly on
the wall, precluding practical use.
[0137] (Drying Properties)
[0138] The various water-soluble adhesives indicated in Table 4
were diluted 1:1 with water and applied over an area of
90.times.180 cm with an automatic wallpaper paster (made by Kyokuto
Sanki K.K.) to the back layer (B) side (the paper backing side when
a paper backing was present) of each of the wallpapers and the
wallpapers were quickly hung on a gypsum board wall surface. The
handling properties of this series of operations were evaluated on
the following scale.
[0139] O: The same drying property was exhibited as the natural
paper backing, and handling was easy.
[0140] .DELTA.: Drying was poorer than for a natural paper backing,
and handling was problematic.
[0141] X: Drying was poorer than for a natural paper backing,
precluding practical use.
[0142] (Ease of Rehanging)
[0143] The various water-soluble adhesives indicated in Table 4
were diluted 1:1 with water and applied with an automatic wallpaper
paster (made by Kyokuto Sanki K.K.) to the back layer (B) side (the
paper backing side when a paper backing was present) of each of the
wallpapers and the wallpapers were quickly hung on a gypsum board
wall surface. After seven days had elapsed, the various
multilayered-stretched resin films were peeled off the wall.
Consequently, the various water-soluble adhesives indicated in
Table 4 were diluted 1:1 with water and applied with an automatic
wallpaper paster (made by Kyokuto Sanki K.K.) to the peeled
surfaces of the various multilayered-stretched resin films that had
been peeled off and the wallpapers were quickly hung on a gypsum
board wall surface. After seven days had elapsed, adhesives tape
(product name "Cellotape", made by Nichiban (K.K.)) was adhered to
each of the multilayered-stretched resin films, adequate pressure
was applied, the wallpaper was cut to the width of the tape with
knife, the adhesive tape was pulled by hand from the gypsum board
panel at an angle of 90 degrees at a fixed rate, and an evaluation
was conducted on the following scale:
[0144] O: Resistance present during peeling, peeled away from the
back layer (B) portion.
[0145] .DELTA.: Resistance present but weak during peeling when
peeled from the readhered surface, with partial separation of back
layer (B) form the readhered surface. Practical problems
present.
[0146] X: Back layer (B) peeled away form the readhered surface and
there was little resistance during peeling. Practical use was
precluded.
[0147] 7) Suitability for Recycling
[0148] Various wallpapers that had been hung were peeled off after
one month had elapsed, the peeled wallpaper was placed in a
pulverizer and chipped. The mass was again melted and extruded by a
twin-screw extruder equipped with a 100-mesh screen pack where the
temperature was set to 60.degree. C. higher than the melting point
of the high-melting-point resin material employed. The second melt
extrusion (regeneration) was evaluated as being possible or
impossible based on clogging of the screen pack, smoking from an
extruder, and change in color of the recycled resin as a result of
this process.
[0149] The results of the above test examples are presented in
Table 4.
3 TABLE 3 Composition Front surface layer (A) Back surface layer
(B) Thermoplastic Thermoplastic Hydrophilic resin Elastomer
Firepowder resin Elastomer resin Firepowder ratio ratio ratio ratio
ratio ratio ratio type (wt %) type (wt %) type (wt %) type (wt %)
type (wt %) type (wt %) type (wt %) Ex. 1 a 30 a 20 .alpha. 1 50 d
25 a 20 1 5 .gamma. 50 2 b 35 b 15 .beta. 50 d 20 a 25 1 10 .gamma.
45 3 a 45 a 30 .alpha. 1 25 d 10 a 25 2 5 .gamma. 60 4 f 35 a 10
.alpha. 1 55 d 30 a 15 -- -- .gamma. 55 5 a 40 b 25 .beta. 35 e 10
a 15 1 10 .gamma. 65 6 a 30 a 20 .alpha. 1 50 d 25 a 20 1 5 .gamma.
50 Comp. 1 a 40 b 10 .alpha. 1 50 e 35 b 5 -- -- .gamma. 60 Ex. 2 a
30 a 20 .alpha. 1 50 d 25 a 20 1 5 .gamma. 50 Composition
Intermediate layer (C) Thermoplastic Hydrophilic resin Elastomer
resin Firepowder Stretching conditions ratio ratio ratio ratio
temp. ratio type (wt %) type (wt %) type (wt %) type (wt %)
direction (.degree. C.) (fold) Ex. 1 -- -- -- -- -- -- -- --
uniaxial 120 5 2 -- -- -- -- -- -- -- -- uniaxial 130 4 3 -- -- --
-- -- -- -- -- uniaxial 130 6 4 d 40 a 33 1 2 .gamma. 25 biaxial
130/155 5 .times. 9 5 d 32 a 43 1 10 .gamma. 15 uniaxial 125 5 6 d
20 a 45 1 10 .gamma. 25 uniaxial 140 5 Comp. 1 c 50 b 20 -- --
.alpha. 2 30 uniaxial 125 5 Ex. 2 d 50 b 20 1 15 .gamma. 15 not
stretched -- --
[0150]
4 TABLE 4 Evaluation Multilayered-stretched resin film Print- Wa-
ing ter Water suita- Embossing Recycling con- absorb- bility
suitability properties tact ance Ability Abil- Ease of hanging Con-
angle Peel volume to ity to Re- dition of strength (mL/ adhere take
han- Dry- hang- Per- of Porosity (%) Density layer of layer
m.sup.2) of to ink em- Re- dling ing ing mitted ex- Layer Layer
Layer (g/ (B) (B) layer of layer boss- ver- Ad- prop- prop- prop-
re- trud- (A) (B) (C) Total cm.sup.3) (.degree.) (g/cm) (B) (A) ing
sion hesive erty erty erty melting ing Ex. 1 20 40 -- 34 0.84 30 92
20 .largecircle. .largecircle. .circleincircle. (1) .largecircle.
.largecircle. .largecircle. Yes Good 2 18 39 -- 30 0.91 35 110 15
.circleincircle. .largecircle. .circleincircle. (1) .largecircle.
.largecircle. .largecircle. Yes Good 3 25 52 -- 39 0.66 20 65 32
.circleincircle. .largecircle. .largecircle. (1) .largecircle.
.largecircle. .largecircle. Yes Good 4 28 57 48 51 0.47 16 40 42
.largecircle. .largecircle. .DELTA. (2) .largecircle. .largecircle.
.largecircle. Yes Good 5 23 52 44 49 0.68 25 75 30 .largecircle.
.largecircle. .largecircle. (3) .largecircle. .largecircle.
.largecircle. Yes Good 6 5 33 18 26 0.97 50 165 8 .circleincircle.
.DELTA. .circleincircle. (2) .largecircle. .largecircle.
.largecircle. Yes Good Comp. 1 15 40 33 31 0.85 55 95 5
.largecircle. .largecircle. .circleincircle. (1) X .DELTA. .DELTA.
Yes Good Ex. 2 1 1 1 1 1.24 88 350 1 .DELTA. .DELTA. X (1) X X X
Yes Good 3 Natural paper employed as -- -- -- 45 .DELTA. .DELTA. X
(1) .DELTA. .largecircle. *.DELTA. No Clog- backing in Comp. ged
Example 2 4 Commercial PVC foam -- -- -- 55 -- -- -- (1)
.largecircle. .largecircle. *X No Clog- wallpaper ged Note: Items
in the Rehanging column with an * denote that the natural paper
backing served as the readhesion surface.
INDUSTRIAL APPLICABILITY
[0151] The multilayered-stretched resin film of the present
invention affords good properties as wallpaper, such as suitability
for printing and embossing. Further, the wallpaper is readily
applied to a wall surface or the like due to the imparting of the
water absorption of a water-soluble adhesive to back layer (B).
Further, the peel strength of back layer (B) of the
multilayered-stretched resin film of the present invention is set
to from 10 to 200 g/cm, causing the back layer (B) portion to
remain on the wall surface when the wallpaper is peeled off. Thus,
the peeled multilayered-stretched resin film does not contain other
materials such as a natural paper backing, pressure-sensitive
adhesive, or water-soluble adhesive, permitting recycling without
the separation of such materials. Further, rehanging on the wall
surface from which the wallpaper has been peeled is possible by
reapplying a water-soluble adhesive, rendering the
multilayered-stretched resin film of the present invention
extremely useful as an interior design material.
* * * * *